Resistor value??

[unit100]

Can someone tell me a general value of the large balance resistor for my Apache 4 pill amp? The large one where the output transformers are. I overdrove it, and it burned it black and I can't see the colors. I know...probably dropped some pills too.

It has 4 1446's, and was doing about 500 PEP. I am not a repair type person, but would imagine some calculations have to take place here.

Thanks

 

[bettyeboop]

is there also a silver mica cap going from the combiner to ground....or a metal mica???

Lift up the leg of each pill that is on the top like you were reading the pill info....it is also the leg with the corner cut off. then take an ohm meter and ck it like a diode......the values should be close on all four pills......this works most of the time....I get some false negitives sometimes where the pill will still work. IT is better just to replace it.....is the little resistors going from the input end going to ground.....if they are burned you have a pill burned most likely. If two are bad i replace all of them and put the two good ones in my used parts bin. cb tricks should have a amp or one close to find your values. are you talking about the resistor that is built in the combiner or just a final resistor before going to the relay???? Spend some time with your meter....... Good luck

galyn davis

 

[unit100]

Combiner

I am not sure what a combiner is unless its the choke at the output of the output transformers that has several wires circling a round ferrite. The large burned resistor is the one that crosses from the two seperate outputs. There is a ceramic capacitor in there also.

There is a burned resistor that goes to ground on the side of one outer pill. I'm sure its a goner.

Thanks for the answer, and I'm off to check CB Tricks also.

Buddy S.

 

[bushwacker]

usually its 100 ohm resistor if this is a 4 pill. The idea is you have 1, 50 ohm input being split into2, 50 ohm outputs......2 x 50 ohms is 100ohms. The "balancing resistor" is usually double the input resistance or in this case....100ohms. Using 100 ohms will give you 50ohms on each side.

100 ohms will be fine....... it sould be the same value as the balncing resistor used at the input side. The balancing resistor sets the resistance of the 2 outputs of the combiner/splitter.

Check for burnt small value resistors ( usually around 10 or 12 ohms) that run from base (input) to ground.... should be 1 resistor per pill.... usually if those are burnt , the pill is history. Its a good indication of which pills to check first.
Personally I would lift the base and collecter tab and check them all....but at least you can get some idea of which one should be bad by looking for those burnt 10 ohm resistors.

 

[unit100]

Thats what I thought

Thanks guys. I looked up a 4 pill on CB tricks and I determined 100 ohm and 10 ohm respectively also. Wish I knew as much as you guys, but basically all I know is heat the iron, remove a part and replace it with a new one.

What happened was I was trying to drive this amp with a little 2 pill that swings from a couple watts to 100. The 4 pill obviously could'nt take it. But, I think I can get it from here. If not, I'll be hollerin'.

73's
Buddy

 

[Beetle]

When you're replacing the resistors, be sure what you install is the proper resistance value AND power-handling capacity.

And watch out for resistors that have measurable amounts of inductance, like wire-wound power resistors. RF doesn't like them - it's funny that way.

 

[bushwacker]

When you're replacing the resistors, be sure what you install is the proper resistance value AND power-handling capacity.

And watch out for resistors that have measurable amounts of inductance, like wire-wound power resistors. RF doesn't like them - it's funny that way.

YES.....excellent point to bring up.
Don't use wire wound.

 

[mackmobile43]

And you'll find out the even though it's called a balance resistor that single 2 or 5 watt 100 ohm resistor is merely an indicator of other problems because if it were large enough to carry half of the amps total output it would need to be capable of handling atleast 250 watts on a 4/1446 amp.

By the very nature that the balance resistor is toast in your amp would indicate just that, an imbalance in the load the combiner is seeing and by that I mean that one or more of your output transistors has failed due to what it's suppose to do and that is to create power and if one side of it has failed then you're only producing half power and the 2 or 5 watt 100 ohm resistor can't handle it and went up in smoke.

So you'll need to be searching for the reason for the imbalance to cure the output combiner resistor problem.

Look for the 10 ohm resistors from the transistor base to be toast and that will usually indicate which 2 transistor section has the bad transistors.

Always remember, there's a reason that the coax is connected while you're transmitting.